Selective association of electrocardiographic abnormalities with insulin sensitivity and beta-cell function in type 2 diabetes mellitus: a cross-sectional analysis

Background: We investigated the association of electrocardiographic (ECG) abnormalities with markers of insulin resistance and pancreatic beta-cell dysfunction in a cross-sectional study of type 2 diabetes patients. Methods: Electrocardiographic criteria were evaluated in the Penn Diabetes Heart Study participants (n = 1671; 64% male; 61% Caucasian), including a sub-sample (n = 710) that underwent oral glucose tolerance testing. The Matsuda Insulin Sensitivity Index and homeostasis model assessment of insulin resistance (HOMA-IR) estimated insulin sensitivity; Insulinogenic Index and homeostasis model assessment of beta-cell function assessed beta-cell function. Multivariable regression modelling was used to analyse associations of ECG changes with these indices. Results: In unadjusted analyses, subjects in the highest quartile of Matsuda index had the lowest prevalence of Q-waves (6.3% versus 15.3%, p = 0.005). In adjusted models, an inverse association was seen between Q-waves and log Matsuda index [one standard deviation increase; OR = 0.59 (95% CI 0.43-0.87 p = 0.001)]. In the full Penn Diabetes Heart Study, there was a direct association between Q-waves and HOMA-IR [one standard deviation increase; OR = 1.43 (95% CI 1.13–1.81, p = 0.003)]. In adjusted models, left ventricular hypertrophy also was inversely associated with Matsuda index and directly with HOMA-IR. Higher Insulinogenic Index scores were associated with a lower prevalence of nonspecific ST changes [OR = 0.78 (95% CI 0.62–0.98, p = 0.032)]. Conclusions: In type 2 diabetic patients, both oral glucose tolerance testing-derived and HOMA-derived measures of insulin resistance were associated with pathologic Q-waves and left ventricular hypertrophy on ECGs.